1. Field of the Invention
The present invention relates to a light source unit and a projector.
2. Description of the Related Art
In these days, data projectors are used on many occasions as image projection units which project images including images of screens of personal computers and video images, as well as images based on image data which is stored in memory cards on to a screen. In these projectors, light emitted from a light source is collected on to a micromirror display device called a digital micromirror device (DMD) or a liquid crystal plate for projection on to a screen as color images.
Conventionally, the mainstream of these projectors has been those which use a high-intensity discharge lamp as a light source. However, in recent years, there have been made many developments and proposals on projectors which use, as a light source, red, green and blue light emitting diodes or a solid light emitting device such as a device utilizing organic EL technology.
For example, Japanese Unexamined Patent Publication No. 2004-341105 (JP-A-2004-341105) proposes a method for generating light of a plurality of colors by coating a substrate with different types of luminescent materials which emit light of different wavelengths, rotating the substrate and shining ultraviolet excitation light on to the rotating substrate.
In JP-A-2004-341105, however, the time-sharing ratio for each color is determined simply by an angle at which the substrate is coated with the luminescent material corresponding to that color. Therefore, for example, the angles at which the substrate is coated with the luminescent materials cannot be changed to arbitrary angles during the operation of the projector. Thus, in order to control the variation in quantity of light for each color during the operation of the projector, substrates which are coated with luminescent materials at different angles have had to be replaced.